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Polymer donors with hydrophilic side-chains enabling efficient and thermally-stable polymer solar cells by non-halogenated solvent processing

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Nano Research Energy 2024年第1期3卷 19-29页

作者： Soodeok Seo jun-Young park Jin Su park Seungjin Lee Do-Yeong Choi Yun-Hi Kim Bumjoon J.Kim Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Materials Engineering and Convergence Technology and ERI Gyeongsang National UniversityJinju 52828Republic of Korea Advanced Energy Materials Research Center Korea Research Institute of Chemical Technology(KRICT)Daejeon 34114Republic of Korea Department of Chemistry and ERI Gyeongsang National UniversityJinju 52828Republic of Korea

Polymer solar cells(PSCs)with high power conversion efficiency(PCE)and environment-friendly fabrication are the main requirements enabling their production in industrial *** the use of non-halogenated solvent processing is inevitable for the PSC fabrication,it significantly reduces the processability of polymer donors(PDS)and small-molecule acceptors(SMAs).This often results in unoptimized blend morphology and limits the device *** address this issue,hydrophilic oligoethylene glycol(OEG)side-chains are introduced into a PD(2EG)to enhance the molecular compatibility between the PD and L8-BO *** 2EG PD induces higher crystallinity and alleviates phase separation with the SMA compared to the reference PD(PM7)with hydrocarbon ***,the 2EG-based PSCs exhibit a higher PCE(15.8%)than the PM7-based PSCs(PCE=14.4%)in the ortho-xylene based ***,benefitted from the reduced phase separation and increased crystallinity of 2EG PDS,the 2EG-based PSCs show enhanced thermal stability(84%of initial PCE after 120 h heating)compared to that of the PM7-based PSCs(60%of initial PCE after 120 h heating).This study demonstrates the potential of OEG side-chain-incorporated materials in developing efficient,stable,and eco-friendly PSCs.

关键词： polymer solar cell polymer donor OEG side-chain non-halogenated solvent process side-chain engineering

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EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： LEE Jeung-Hoon junG jae-Kwon LEE Kyung-jun HAN jae-Moon park Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent

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A nanofilter composed of carbon nanotube-silver composites for virus removal and antibacterial activity improvement

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Journal of Environmental Sciences 2016年第4期28卷 275-283页

作者： jun Pyo Kim jae Ha Kim Jieun Kim Soo No Lee Han-Oh park Nano Development Team Bioneer Corporation Daejeon 306-220 Republic of Korea

We have developed a new nanofilter using a carbon nanotube-silver composite material that is capable of efficiently removing waterborne viruses and *** nanofilter was subjected to plasma surface treatment to enhance its flow rate,which was improved by approximately 62%.Nanoscale pores were obtained by fabricating a carbon nanotube network and using nanoparticle fixation technology for the removal of *** pore size of the nanofilter was approximately 38 nm and the measured flow rate ranged from 21.0 to 97.2 L/（min·m^2）under a pressure of 1–6 kgf/cm^2 when the amount of loaded carbon nanotube-silver composite was 1.0 mg/cm^*** nanofilter was tested against Polio-,Noro-,and Coxsackie viruses using a sensitive real-time polymerase chain reaction assay to detect the presence of viral particles within the *** trace of viruses was found to flow through the nanofilter with carbon nanotube-silver composite loaded above 0.8 mg/cm^***,the surface of the filter has antibacterial properties to prevent bacterial clogging due to the presence of 20-nm silver nanoparticles,which were synthesized on the carbon nanotube surface.

关键词： Carbon nanotube Silver nanoparticle Virus removal Nanofilter Water purification

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EFFECT OF FABRICATION ON HIGH CYCLE FATIGUE PROPERTIES OF COPPER THIN FILMS

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Acta Mechanica Solida Sinica 2008年第4期21卷 318-326页

作者： jun-Hyub park Joong-Hyok An Yun-jae Kim Hyeon-Chang Choi Department of Mechatronics Engineering College of EngineeringTongmyong University535Yongdang-DongNam-GuBusan608-711Korea Department of Mechanical Engineering College of EngineeringKorea UniversityAnam-dong Seongbuk-GuSeoul136-701Korea

The influence of fabrication on the tensile and fatigue behavior of copper films manufactured by 3 kinds of fabrication methods was investigated. The tensile and high cycle fatigue tests were performed using the test machine developed by authors. Young＇s moduli （72, 71 and 69 GPa, respectively） are lower than the literature values （108-145 GPa）, while the yield strengths were as high as 358, 350 and 346 MPa, respectively and the ultimate strengths as 462, 456 and 446 MPa, respectively. There is not much difference in the tensile properties of the 3 kinds of films. There is little difference in the fatigue properties of the 3 kinds of films but one of them has shorter fatigue life than others in high cycle region and longer fatigue life than others in low cycle region.

关键词： mechanical properties thin film copper high cycle fatigue test

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Risk factors for rebleeding after angiographically negative acute gastrointestinal bleeding

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World Journal of Gastroenterology 2009年第32期15卷 4023-4027页

作者： Ijin Joo Hyo-Cheol Kim Jin Wook Chung Hwan jun jae jae Hyung park Department of Radiology Seoul National University College of Medicine Institute of Radiation Medicine Seoul National University Medical Research Center Clinical Research Institute Seoul National University HospitalSeoul 110-744South Korea

AIM:To identify possible predictive factors for rebleeding after angiographically negative findings in patients with acute non-variceal gastrointestinal ***: From January 2000 to July 2007, 128 patients with acute non-variceal gastrointestinal bleeding had negative f indings after initial angiography. Clinical and laboratory parameters were analyzed ***: Among 128 patients, 62 had no recurrent gastrointestinal bleeding and 66 had recurrent gastrointestinal bleeding within 30 d. As determined by the use of multivariate analysis, an underlying malignancy, liver cirrhosis and hematemesis were significant factors related to recurrent gastrointestinal ***: Clinical factors including underlying malignancy, liver cirrhosis, and hematemesis are important predictors for rebleeding after angiographically negative findings in patients with acute non-variceal gastrointestinal bleeding.

关键词： Angiography Gastrointestinal hemorrhage Predictive factor

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Angiosperm-wide analysis of fruit and ovary evolution aided by a new nuclear phylogeny supports association of the same ovary type with both dry and fleshy fruits

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Journal of Integrative Plant Biology 2024年第2期66卷 228-251页

作者： Yezi Xiang Taikui Zhang Yiyong Zhao Hongjin Dong Hongyi Chen Yi Hu Chien-Hsun Huang jun Xiang Hong Ma State Key Laboratory of Genetic Engineering Ministry of Education Key Laboratory of Biodiversity and Ecological EngineeringInstitute of Plant BiologyCenter of Evolutionary BiologySchool of Life SciencesFudan UniversityShanghai 200438China Department of Biology Howard Hughes Medical InstituteDuke UniversityDurhamNC 27708USA Department of Biology the Eberly College of Scienceand the Huck Institutes of the Life Sciencesthe Pennsylvania State UniversityUniversity ParkPA 16802USA Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization College of Biology and Agricultural ResourcesHuanggang Normal UniversityHuanggang 438000China

Fruit functions in seed protection and dispersal and belongs to many dry and fleshy types,yet their evolutionary pattern remains unclear in part due to uncertainties in the phylogenetic relationships among several orders and *** we used nuclear genes of 502 angiosperm species representing 231 families to reconstruct a well supported phylogeny,with resolved relationships for orders and families with previously uncertain *** this phylogeny as a framework,molecular dating supports a Triassic origin of the crown angiosperms,followed by the emergence of most orders in the Jurassic and Cretaceous and their rise to ecological dominance during the Cretaceous Terrestrial *** robust phylogeny allowed an examination of the evolutionary pattern of fruit and ovary types,revealing a trend of parallel carpel fusions during early diversifications in eudicots,monocots,and ***,taxa in the same order or family with the same ovary type can develop either dry or fleshy fruits with strong correlations between specific types of dry and fleshy fruits;such associations of ovary,dry and fleshy fruits define several ovaryfruit"modules"each found in multiple *** of the frequent modules has an ovary containing multiple ovules,capsules and berries,and another with an ovary having one or two ovules,achenes(or other single-seeded dry fruits)and *** new perspective of relationships among fruit types highlights the closeness of specific dry and fleshy fruit types,such as capsule and berry,that develop from the same ovary type and belong to the same module relative to dry and fleshy fruits of other modules(such as achenes and drupes).Further analyses of gene families containing known genes for ovary and fruit development identified phylogenetic nodes with multiple gene duplications,supporting a possible role of whole-genome duplications,in combination with climate changes and animal behaviors,in angiosperm fruit and ovary diversificat

关键词： angiosperm fruit evolution MADS-box molecular clock nuclear phylogeny ovary and fruit developmental genes

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High-resolution circulation forecasting of the Maenggol Channel, south coast of Korea

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Acta Oceanologica Sinica 2015年第12期34卷 11-18页

作者： CHOI Jinyong jun Kicheon CHOI Youngkwang CHO Kyoungho KWON jae-Il park Jinsoon park Kwangsoon Operational Oceanography Research Center Korea Institute of Ocean Science and Technology Task Force for Construction of RV ISABU Support Facility Korea Institute of Ocean Science and Technology Division of Polar Ocean Environment Korea Polar Research Institute China-Korea Joint Ocean Research Center Coastal Development Research Center Korea Institute of Ocean Science and Technology

The Maenggol Channel and Uldolmok Strait, located on the south-west coast of Korea, have notably strong and complex currents due to tidal effects and to local geological factors. In these areas, electric power has been generated using strong tidal currents, the speed of which is more than 3 m/s during spring tides. The region also provides a shortcut for navigation. These tidal conditions are therefore sometimes useful, but may also cause terrible accidents or severe economic damage, in the absence of accurate information regarding ocean conditions. In April 2014, the passenger ferry MV Sewol capsized in the Maenggol Channel, with 295 passengers killed and 9 still missing. While this was unquestionably a man-made disaster, strong currents were one of the contributing causes. It was also difficult to conduct scuba diving rescue operations given strong current speeds,and accurate prediction of the time when the tide would turn was thus critically needed. In this research, we used the high-resolution coastal circulation forecasting system of KOOS（Korea Operational Oceanographic System） for analysis and simulation of strong tidal currents in such areas with many small islands, using measurements and modeling from this research area. For accurate prediction of tidal currents, small grid size-modeling was needed,and in this study, we identified a suitable grid size that offers efficiency as well as accuracy.

关键词： Maenggol Channel Sewol ferry accident circulation forecasting

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Effects of Al addition on microstructure and mechanical properties of extruded Mg-3Bi alloy

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Journal of Magnesium and Alloys 2022年第7期10卷 1887-1898页

作者： Sang-Cheol Jin jae Won Cha jun Ho Bae Hui Yu Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea School of Materials Science and Engineering Hebei University of TechnologyTianjin 300130China

Effects of Al addition to a Mg±Bi binary alloy on its microstructural characteristics and tensile properties after extrusion are investigated via extrusion of Mg-3Bi±x Al(x=0,1,and 2 wt%)billets and analysis of the extruded *** Al addition negligibly affects the second-phase particles of the extruded alloy;however,an increase in the Al content causes significant decreases in the average grain size and maximum texture intensity of the extruded material owing to an increase in the area fraction of dynamically recrystallized(DRXed)*** Al addition improves the strength of the extruded alloy;this improvement is attributed to the enhanced grain-boundary hardening and solid-solution hardening effects induced by grain refinement and Al solute atoms,*** the Al content increases from 0 wt%to 1 wt%and 2 wt%,the tensile elongation increases substantially from 2.8%to 9.4%and 16.9%,*** reduction in the number and size of un DRXed grains with increasing Al content suppresses the formation and coalescence of cracks in the un DRXed grains during tension,which results in a significant improvement in the tensile ductility of the extruded *** tensile deformation,large undesirable twins that act as crack initiation sites are locally formed in the un DRXed grains of the Mg-3Bi alloy,whereas relatively smaller twins are uniformly formed in both the DRXed and the un DRXed grains of the Mg-3Bi-2Al ***,the extruded Mg-3Bi-2Al alloy has a substantially higher tensile yield strength±elongation product(2924 MPa%)than the extruded Al-free B3 alloy(381 MPa%).

关键词： Mg-Bi-Al alloy Extrusion Microstructure Strength Ductility

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Comparative study of extrudability, microstructure, and mechanical properties of AZ80 and BA53 alloys

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Journal of Magnesium and Alloys 2023年第1期11卷 249-258页

作者： Sang-Cheol Jin jae Won Cha Jongbin Go jun Ho Bae Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Kyoto UniversityKyoto 606-8501Japan Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The extrudability,microstructural characteristics,and tensile properties of the Mg–5Bi–3Al(BA53)alloy are investigated herein by comparing them with those of a commercial Mg–8Al–0.5 Zn(AZ80)*** AZ80 is extruded at 400℃,severe hot cracking occurs at exit speeds of 4.5 m/min or *** contrast,BA53 is successfully extruded without any surface cracking at 400℃ and at high exit speeds of 21–40 m/*** extruded at 3 m/min(AZ80–3)and 40 m/min(BA53–40),both AZ80 and BA53 exhibited completely recrystallized microstructures with abasal ***,BA53–40 has a coarser grain structure owing to grain growth promoted by the high temperature in the deformation ***80–3 contains a continuous network of Mg_(17)Al_(12) particles along the grain boundaries,which form via static precipitation during natural air-cooling after the material exits the extrusion ***53–40 contains coarse Mg_(3)Bi_(2) particles aligned parallel to the extrusion direction along with numerous uniformly distributed fine Mg_(3)Bi_(2) ***80–3 has higher tensile strength than BA53–40 because the relatively finer grains and larger number of solute atoms in AZ80–3 result in stronger grain-boundary and solid-solution hardening effects,*** BA53 is extruded at a high temperature and extrusion speed of 400℃ and 40 m/min,respectively,the extruded material has a high tensile yield strength of 188 *** can be primarily attributed to the large particle hardening effect resulting from the numerous fine Mg_(3)Bi_(2) particles.

关键词： Mg-Bi-Al alloy Extrusion Hot cracking Second phase Tensile properties

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An Enhanced Jacobi Precoder for Downlink Massive MIMO Systems

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Computers, Materials & Continua 2021年第7期68卷 137-148页

作者： park Chan-Yeob Hyun-Ro jae jun-Yong Jang Song Hyoung-Kyu Department of Information and Communication Engineering and Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea

Linear precoding methods such as zero-forcing(ZF)are near optimal for downlink massive multi-user multiple input multiple output(MIMO)systems due to their asymptotic channel ***,as the number of users increases,the computational complexity of obtaining the inverse matrix of the gram matrix *** the computational complexity problem,this paper proposes an improved Jacobi(JC)-based precoder to improve error performance of the conventional JC in the downlink massive MIMO *** conventional JC was studied for solving the high computational complexity of the ZF algorithm and was able to achieve parallel ***,the conventional JC has poor error performance when the number of users increases,which means that the diagonal dominance component of the gram matrix is *** this paper,the preconditioning method is proposed to improve the error *** executing the JC,the condition number of the linear equation and spectrum radius of the iteration matrix are reduced by multiplying the preconditioning matrix of the linear *** further reduce the condition number of the linear equation,this paper proposes a polynomial expansion precondition matrix that supplements diagonal *** results show that the proposed method provides better performance than other iterative methods and has similar performance to the ZF.

关键词： Jacobi(JC) massive MIMO precondition polynomial expansion linear precoding

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